Automatic gun charger



24,-1946- 5; w PoNTlus, 313., E.TAL 2,413,113

AUTOMATIC GUN CHARGER Filed Nov. 5, 1942 3 Sheets-Sheet l INVENTORS GEORGE M Pawr/usw ARTHUR R M450 Dec. 1946- G. PONTIUS, 30., ET AL: 2,41 3,1 13

AUTOMATIC GUN CHARGER Filed N06. 5; 1942 s Sheets-Sheet 2 IIVVENTORS 650%,: M Pawr/us Air/m? R MASON Dec. 24, 1946.

G W. PONTIUS, 3D., El AL AUTOMATIC GUN CHARGER- Filed Nov. 5; 1942 3 Sheets Sheet 3 l/V VENTOE-S GEORGE M Pawr/a Patented Dec. 24, 1943 2,413,113 AUTOMATIC GUN George W. Pontius, III, and Arthur P. Wilson, South Bend, Ind., assignors to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Application November 5, 1942, Serial No. 464,609

4 Claims.

This invention relates to charging systems for automatic guns and particularly to automatic charging systems therefor.

In many types of guns the loading operation is performed by the reciprocation of a breech block such as in machine guns and automatic cannon employed in military aircraft. In most of the automatic guns now employed, the reciprocation cf the breechblock and its attendant breech bolt is actuated by the power developed by the firing of a cartridge, which ejects the empty. shell and places a succeeding cartridge in the gun breech ready for firing. If, however, one of these cartridges fails to fire there is no reciprocation of the breech block to eject the faulty cartridge and to insert a fresh cartridge. It may also happen that the moving parts of an automatic gun may become stuck or pinched so that it is unable to operate automatically. In either event, such a gun is termed a jammed gun, and the only way to restore it to automatic operation is to retract the breech bolt by means external to the gun.

In the past it has been customary to retract the breech bolt of a jammed gun by hand. Such an operation is ordinarily not possible in modern military vehicles since the guns may be located remotely from the operator, as, for example, in the wings of a military aircraft. In such a case, to free guns in the manner described, it is known to provide cables running from the wings to the cockpit, which cables can be actuated by the pilot or gunner. Obviously, such an expedient requires an elaborate system of pulleys and long cables, particularly in the case of the larger aircraft now employed, and with the larger caliber guns and cannon now in use it is very difficult to reciprocate the moving parts manually. Further, if the gunner or pilot has other duties, he cannot take the time and effort necessary manually to free and recharge the guns. These and other considerations make it desirable to have a power mechanism for recharging guns in the event of misfire and it is desirable to have this mechanism operate automatically.

' Attempts have been made to provide power means to recharge guns, as for example by use of pneumatic power systems. Some of the pneu matic systems are automatic, using electrical controls to create an automatic action. Invariably, however, in these systems there is a mechanical time lag mechanism such as a dashpot which is reset each time a round is fired. If the gun should fail to fire in a time period longer than the normal time of bolt travel between successive firing of each round. the dashpot will travel through its entire stroke and set the charging system in action. Obviously, the firing of each round places an abusive force on the dashpot, and its life as a result thereof is extremely limited.

Another expedient has been proposed to effect the automatic recharging of guns, which expedient has been the use of automatic electric recharging mechanism. These devices have been open to the objection that oftentimes they are as large as the gun upon which they are used for recharging. Where space and weight are matters of prime importance such an expedient is hardly a desirable one.

This invention improves upon the prior art in that hydraulic fluid is used for eifecting a rechargingoperation, and that electric power is used merely as a controlling means and not as the power meansv as is the case in'an electromechanical charger. Hydraulic fluid has. been found to be most reliable and positive in action and therefore is preferred over pneumatic systems. Too, since hydraulic fiuid is available under pressure in most military vehicles, particularly aircraft, little additional burden is placed upon the power plant as would be the case where an electro-mechanical charging system is employed. Whereas with a pneumatic system the motivating fluid is exhausted to atmosphere at the conclusion of a charging operation, the fiuid used in a hydraulic system is exhausted to a reservoir and may be used over and over again.

This-invention is a further improvement over the prior. art in that an electrical time lag mechanism is employed, thereby saving weight, and also not being open .to'the criticisms and objections inherent in a dashpot used to accomplish the same purpose. The improved charging system comprising this invention is also an improvement over the prior art in that hydraulic fluid under high pressure may be employed, thereby requiring only the use of a small motor having a high power-to-weight ratio thereby adding but little weight to the aircraft. A feature of the invention lies in the use of a single valve to control the nowgor a fluid to a charging motor, small intermediate selector valves being employed to pass fluid only to the charging center of the gun requiring recharging.

Other important features of the invention include a specially designed charging motor using hydraulic fluid, spacedbrackets for holding the charging cylinder to'its gun and permitting easy removal of the charging motor without dismam tling the gun, and a charge counting device to limit the number of charging operations to be applied to a single gun. This last is an important feature, since a gun requiring a large number of charging operations has probably expended its ammunition or is in some way defective. The inventionalso includes means whereby an armcrer .may-reload the gun with .a fresh belt of ammunition or test the operation'of the gun when it is equipped with the improved charging system. There is also provided a cut-out means for stopping a run away gun, which otherwise might be injured by a long burst-of fire.

With the foregoing problems .mind, it is :an object of this invention to provide .an electrohydraulic charging system which is fully automatic, the charging system being applicable to a single gun or to a plurality of guns.

A further object of the invention is to provide an automatic chargingsystem or either a single gun or a plurality of guns which will add but little to the weight era military vehicle.

The still furtherobject is to provide an automatic chargingsystem which is operable by pressure "from a fluid pressure system normally included in a military aircraft.

Yet another object ,is to provide a charging system for several gunsxwherein selector valves draw fluid from aslngle master valveqto the particular gun .or guns requiring charging.

Still another-object is to provide an improved charging motor for use with-hydraulic fluid.

A still further object istoprovide a charging motor which is operable to retract the bolt of a misfiring gun and to hold it in retracted position 2 before freeing it for unimpeded counter movement to the firingposition.

, A still further object contemplates-the provision of means whereby the varmorer of a gun equipped with this invention may reload .a gun with a fresh beltoi ammunition or'test the operation of the gun.

Another object is to provide acharge counter for each gun whichcuts out the-operation of the charging system associated .with eachgun to stop 1 a gun" which aims regardless of whether the sear is actuated or not.

Another object is'to provide a .cuteout mechanism for the firingimotorxof 'animproperly operating gun. a

These and other objects and features of the invention are pointed out in the x following descripticn in terms of the importance thereof which are showninthe. accompanying drawings. It is to be understood,.however, that the drawings are for the purpose .of illustration only and are not designe'das a :definition of the limits of the invention, reference being had to .the appendedclaims for this purpose.

Inthe drawings illustrating a preferred em bodiment of this-invention: -Figure 1 is a diagrammatic plan view of the entire charging systemasapplie'd to a plurality of machine guns;

Figure 2 is a diagrammaticview of amodified form of an automatic charging system'jemploying selector valves for each charging motor;

,Figure '3 is alongitudinal verticalv seg-mentof a charging motor and a cooperating-switchthere; for including a mechanical charge counterj l Figure {i is-a fragmentary elevational view of our improvedcharging cylinder showing its attendant'switch inoutline form, partsof the switch being shown in dotted outline; and

.tions later to be described. The fluid pressure system comprises a reservoir at which supplies fluid to apump 26 and places the fluid under pressurein an accumulator 28. The accumulator 12.8 .is-connectedizbya conduit 30 to each solenoidoperated .valve Valve 32 is connected by a conduit t l-to each charging motor 26, at times supplying iiuid at high pressure from the conduit 3%, and at times exhausting the fluid from the charging motor 23 through a return line 36 to the reservoir 25. The conditions under which the solenoid operated valves 3.2 operate WillI'be-later described.

The electric circuits shown in-Figurei-willgnow be described, and for purposes of simplification willbe described with relation-to one'gun. However, like parts'shown in Figure 1 bear corresponding ordinals and the circuit which will be described'as applied .to onegun is equally applica- V ble to the other gun "22. Electrical energy may be supplied as from arbattery'iifi, which battery passes'current to a slowrelease-relay til through an ignition switch 52. Atbranch of his circuit passes current to-a switch rid-which is held-open during the proper-operation .o'f'its associated gun. Thecircuit which includes the switch 4 3 has also therein an electrical charging counter mechanism 46 which is placed'intermediate the switch 4 1 and the-solenoid operated valve 32.

The control of the charging mechanism :20 and its attendantsolenoid-operated valve 152 is .effectedzby making and breaking the switch M. The circuit eiiectingjtheoperation ,of the switch M comprises the slow releasegrelay lfl whichhas two branches leading toground. Interposedbetween the. relay ii' anjdground is. a manually. operatedzswitchx ifi andzarrearigun switch 56, which is closed and opened by the-reciprocation of the breech pin which-strikes :a switch actuator :51 at the rearward endiOf,ltSfI33llhgUfTGCipIOCQtlOH. A second ground: circuit for theslow release relay iii includes the manually operated switch '48, a forward gun switch: 52 and iajdouble pole switch edtwhich is closed.

Switch 55' isopenat times when thebreech bolt is, in its forward position, but ,is closed by the breech bolto'f the gun ZZ'When the bolt reciprocates during theifiring oiithe .gun.- The :switch is also-closed at the completion of :a charging cycle. Switch :52, which is at the forward end of :the path of reciprocationof :the :breech bolt is normally closed by --said;breech :bolt. .The breech bolt will keep the switchiklosed whenever-the breech :isqclosed, but iw'hen :not "closed by the "breech boltit tends ;=to. open; it'hlus when the breech bolt is ;closed :there wilkbe aground circuit :ior relay :40 through fthe,:switch 15-2 and the switch 5 Grounding relay :40 energizesit,

actuating 'jbell :crard: .1456 "thereby :opening the switch Lifil'ldthlIS cutting off theilow of current :to the solenoid operated .valve .32. .Thus when switch t2 is ;;closed, and the :breech .block of'the gun 22 is rclosed :the '.-relay 4.0 will be grounded, and the only 1efie.ct,1then,=closingthe switch I i-2' will-be to open switch "M when the breech bolt isinza closed :orforward position. i

losing' switch 42 also passes current to one contact of a safety switch 58 which when closed passes current to one contact of the trigger switch 66. Closing trigger switch 66 passes current to a firing motor 62 mounted on each un 22. The firing motor 62 when energized will actuate a sear, not shown, of the gun 22 and will cause the gun to fire provided there is a live cartridge in the firing chamber. Intermediate the switch 60 and the firing motor 62 is a, cut-out mechanism 45 which operates as a unit with an electric counter unit 46. These will be described later in this description. Simultaneous with the closing of the trigger switch 60 is the energization of the relay 64, which opens the switch 54, thus breaking the ground circuit of the relay 40, which thereupon loses its energy. However, relay 4! is of the slow release type and will hold the switch 44 in open position during the particular time period for which the relay is constructed. This period can be any period longer than the time between the firing of each round of gun 22 when firing automatically. When the breech bolt upon firing reaches the rearward end of its travel, the breech bolt closes the switch 50 thereby grounding relay 4!] thereby reenergizing it. This intermittent energization of relay 43 through switch 50 maintains the switch 44 in an open position so that the valve 32 will not be operated.

If the gun should jam, however, relay 40 would not be intermittently energized through switch 50 and at the expiration of the time period of the relay 4!] the switch 44 would close, thereby passing current through the counter 46 and to the solenoid operated valve 32. Upon energization of the solenoid operated valve 32 fiuid is passed from accumulator 28 to the charging motor 20 to retract the breech bolt thereof and recharge or recock the gun 22. When the breech bolt has been retracted by the charging motor 20 the rearward gun switch 50 will close thereby once more energizing the relay 46, and opening switch 44. With the trigger motor in energized condition, and after the breech bolt has returned to the forward position the gun will continue to fire automatically, thereby periodically closing switch 50 and periodically energizing relay 46 to keep the switch 44 open.

If a charging cycle as described above should be started and the firing period then terminated by opening the trigger switch 60 the gun 22 will nevertheless continue to charge. When the firing period ceases as by opening trigger switch 60 the relay 64 will be deenergized, allowing switch 54 to close, thus closing one of the two branch ground circuits for the relay 46. However, after the charging cycle has started switch 52 opens, thus opening the only possible ground circuit for the relay 40, since the other ground circuit to switch 50 is already broken. Thus with both ground circuits open, the relay 46 will continue to be deenergized effecting a charging cycle as previously described, as the switch 44 is already closed.

The electric counter unit 46 i provided to limit Y the number of charges for any one gun, as a gun which requires a large number of charges has expended its ammunition or is probably defective. This counter 46 comprises a plate member 66 having a conductor sector and notches along the edge of another sector. The member 66 rotates about a shaft 68, and brushes contact the conductor sector. A ratchet arm 12 is also pivoted at the end of the shaft 68 and has a pawl 14 pivoted thereto, which contacts the notches of the member 66. The arm 12 is actuated upon the energization of a solenoid 16, which solenoid is energized whenever the switch 44 is closed. That is, each time switch 44 is closed, solenoid 16 receives an impulse of-current from the source to actuate the mechanism 45. Each movement of the arm 72 contacts a succeeding notch on the member 66 and after a predetermined number of current impulses through the solenoid operated valve 32 one of the brush segments Ill will move out of engagement with the conductor sector of member 66 to thereby cut on the flow of current to the solenoid operated valve 32. In this way a, gun which has expended its ammunition and which repeatedly jams will not be charged after a predetermined number of charges have been made.

Since a useless expenditure of power would be attendant upon the continued energization of the firing motor 62 of a gun which has been cut out from the system by the counter mechanism 46, a firing motor cut out is incorporated into the system for deenergizing the firing motor of such a gun. This cut-out mechanism consists of a unit 45 connected to the charge counter by the shaft 63. The unit comprises a circular disk 4'! of the same dimensions as the member 66 and having a conductor sector 49 like that of member 66. Two brushes 4941 contact the conductor sector 49 and pass current to the trigger motor 62 when both are in contact with the conductor sector 49. When the counter mechanism 46 cuts out its attendant gun, the firing motor cut-out likewise cuts out the firing motor 62 of the same gun.

The switch 48 is manually operable, and by holding switch 48 open current cannot pass through the relay 4!] as both its ground circuits will be broken, thereby dissipating its energy, thus closing switch 44 effecting a, charging operation as described above. By means of switch 48 the gunner may charge any gun if he has reason to doubt that it is not in an operative condition, or if there is a runaway gun. This gun may be effectively stopped by opening switch 48, which also causes any gun to be charged; By holdin switch 48 open the associated gun will charge and the breech bolt will be held in a retracted position, and if the object in so doing is to cool ofia runaway gun, this switch can be kept open until such a gun is cooled to the point where another burst of firing will not injure it.

A ring 18 is provided to actuate one member of switch 52. This ring is used by the armorer when reloading the gun with a new belt of ammunition. By pulling on ring 78 the ground of relay 4!] will be broken and if the pull is of a duration long enough to allow relay 46 to deenergize before releasing ring 78 current will thereby pass to the solenoid of valve 32 to effect a charge. If a live cartridge remains in the firing chamber, it will, of course, be ejected by the charging operation. The first link of a new belt is then inserted in the feedway of gun 22 and ring 18 is again pulled as before, allowing the gun pawl to engage the first live round. Following these operations, one more charging cycle must be performed before the gun will fire. This charge is usually performed by the gunner, just prior to combat by manually opening switch 48. This charging sequence is followed to provide an additional safety feature and makes possible the reloading of the gun while performing a minimum of manual operations upon it.

The details of construction of the charging cylaria-11s inder will be later described as well as the construction of the brackets which holdthecharging motor 2a to the gun 22.

With reference to Figure 2 .of thedrawings there shown an automatic machine gun charger employing a selector valve system. The selector valve system differs from the system shown in Figure l in that each charging motor 28 has a selector valve 39 for controlling the flow of fluid from the single master valve 32. The selector valves are connected to a common hydraulic fluid line t2 to'the master valve I8 and are selectively opened to charge the proper gun. The selector valve 8% is open only when there is no iiuid pressure in the line to the charging motor 2E and. therefore needs to employ only a small and light weight solenoid 84. In most installations there is a saving in weight by the use of selector valves making the system very desirable for aircraft.

The electricalcircuit for the selector valve system of Figure .2 is basically the same as for the system shown in Figure 1. Closing switch 42 passes current to relay AI which as in Figure 1 has two ground circuits one through switch and the other through switches 52 and 54. Relay lU, when energized, acts through'a bellcrank 86 to open switch M to master valve 32 in much the same way as in Figure 1. Bell crank 86 differs from bell crank 56 of Figure 1, however, in that it is a conductor of current, passing current through its length when switch M closes, the other end of hell crank 86 forming also a part of switch 88 at the same-time it operates switch 44. When relay 48 is deenergized and the bell crank 86 is released, current flows from switch 44 to master valve and in addition through bell crank '23 to switch point 38 and through a conductor to the solenoid 3d of selector valve BI), thus when the relay ii} is deenergized current is passed to the selector valve 89 associated with a misfiring gun and to the master valve 32.

The selector valve 3% is a simple solenoid operated or poppet valve of any suitable construction. The solenoid 8. 3 employed may be made very small, and. it therefore desirable that means be provided to insure that there will be no pressure on the line 32 when it is operated. The means provided includes a bell crank 96 for grounding the master valve 32, which switch is operated by the opening movement of selector valve at. A movable core 92 of the solenoid valve 8E! actuates the bell crank 99, which closes a switch 93 thereby grounding the circuit to master valve 32. lector valve as will always be open before fluid under pressure is passed to the charger motor 28.

The selector valve system employs mechanical charge counters, and these will be next described along with the charging cylinder 20. The electrical counters Q5 of Figure 1 could also be applied and could be in the selector valve circuit with equal effect, and the mechanical charge counters associated with the charging motors could also be appiied to the system of Figure 1 with equal effect.

Referring now to Figures 3, 4 and 5 there is shown the charging motor 2i! of Figures 1 and 2. Although this charging unit is well suited for the automatic systems here described, it is applicable also to any type of gun charging system. The unit may be .used on a manually controlled system, and for such use none of the electrical features of the present systems would be used. A manually controlled system in which this unit This construction insures that the se- CJI 8 could be usedis describedin the copending application of 'White and Pontius, Ser. No. 311,978, filed January '2, 1940, now Patent No. 2,332,419. The charging motors can also be used in a semiautomatic system such as described in the application of Pontius, Ser. No, 319,925, filed February 20, 1M0, now Patent No. 2,355,179. Other uses andapplications of the charging unit canibe made and it is not intended to limit its use to the present systems.

The charging motor 29 comprises a cylindrical casing iI'Elsl within which a cylindrical piston I02 reciprocates. The right-hand end of the unit is toward the front of the gun on which it is mounted, and the left-hand end of the unit is secured to the rear of the gun. Thepiston I02 contacts a breech pin IM (shown in dotted outline) and moves the breech block of the gun 22 rearwardly by acting on breech pin IM during a charging operation. Fluid under pressure is directed into the cylinder its at the fitting I06, which may be connected to either the selector valve of Figure 2 or directly to the solenoid operated valve 32 of Figure 1. The cylinder I00 is held to the gun by a forward bracket Hi8 and bya rear bracket H0.

The piston m2 is held in a forward position by a spring H2 which fits inside cylinder I00 and extends into piston Hi2. Spring H2 is mounted on a-two-part tubular telescoping spring guide, one part of which comprises an outer member 1 i i, the otherpart being an inner tubular membeer I 15 secured to the piston Hi2. As the piston m2 reciprocates within cylinder Iilll under the influence of fluid pressure and thespring I I2, the inner member H6 telescopes in the stationary outer member I I4.

A pointed pin H8 slides in guide member H4 and .has an extended shank I20 which passes through a construction in the inner end of guide member H6, and has a head i-2.2 attached to the end of the shank IZIl. The relationship of parts is such that the last portion of the rearward movement of piston I02 causes the inner telescoping member H6 to contact the pin H8 and move it rearwardly. The last part of the forward'niovement of piston I532 causes the constricted end of guide tube l-IE to act onthe head I22 of shank I28 to pull the pin H3 forward.

These movements of pin H8 cooperate-with a breech bolt latch to hold the breech bolt in a retracted position after the charging stroke until the piston I82 has returned nearly to its starting position, permitting the unimpeded movement of the breech pin upon its return to the forward position. The breech pin latch includes a rocker arml 24 pivoted at I26to the rear support bracket I it]. Pivoted at the forward end of the rocker arm I24 is a catch finger I28 pivoted at I35 and urged by a leaf spring I32 to a catch position. At'the rear end of the rocker arm I24 is a roller I34 designed to reduce friction when the rocker arm is-contacted by the pin I I8. Also secured to the rear end of the rocker arm IM is a leaf spring I36 which contacts the bracket I I0, and normall maintains the arm I24 in a disengaged l Qsition. A fitting I38 on the rear end of cylinder I00 has secured thereto a roller Idll to provide a thrust bearing when the pin I I8 strikes the rocker arm roller I34. v

The operation of thecharging motoras thus far described is as follows. Charging fluid from any suitable control device, manual or automatic, enters the cylinder IE0 at the fitting I06 and forces the piston I02 to-the left, and in so doing H8 forces the rocker arm I24 to pivot about I20 against the load in spring I36 so that the rocker arm I 24 assumes a nearly horizontal position. In

that position the latch I28 is in the path of the breech pin I04, as shown by the dotted outline of the latch I28. As the breech pin I04 nears the end of its permissive travel, it strikes the latch I20 and causes it to rotate about its pivot against leaf spring I32, allowing the breech pin I04 to pass. Once the breech pin I04 is past the latch I28 the spring I32 causes the latch to snap back to its normal position, locking the breech pin in its retracted position.

When the piston of the charging cylinder 20 reaches the end of its stroke the charging fluid is cut oil from the pressure source and ported to atmosphere either automatically or manually. Spring I I2 now forces the piston I02 to its starting position forcing out the fluid to atmosphere. The latch I28 on the rocker arm I24 holds the breech pin I04 and its breech bolt in a retracted position until the piston' I02 is out of the path of travel of the breech pin I 04 to allow the breech bolt to have unimpeded action on the closing stroke. The release of the breech pin I04 is accomplished by pulling the pin IIS from between the rollers I40 and I34, which removal allows the rocker arm I24 to rotate about its pivot to render the latch I28 inoperative. The pin H8 is pulled from between the rollers by the restriction in the inner tubular member H6 striking the head I22 on the shank I20 of the pin II8 as the piston I02 is moved to its starting position. The arrangement of the parts is such that the pin I I 8 is pulled out from between rollers only when the piston I02 has reached its starting position and out of the path of travel of the breech pin I04. As described, the device is a charging unit which will hold the breech bolt in a retracted position until the charging piston has withdrawn from the path of travel from the breech pin.

The charging unit as applied to the systems herein described incorporates further features. The actuator switch 50 is also shown in detail ir. Figure 3. The switch 50 is operated by a switch actuator I which is secured to the bottom of the switch 50. At every reciprocation of the breech bolt, Whether during automatic firing or during a charging cycle, the breech pin I04 strikes the switch actuator 5| which in turn closes the switch 50. It will be noted that the switch 50 is of the snap spring type wherein a small movement of the actuator in one direction causes a relatively large movement in the opposite direction.

The charging unit as shown in Figure 3 incorporates a mechanical charge counter. Mounted on'the rear bracket I I0 is an arm I42 supporting a rotatable ratchet wheel I44 which has a re-- moved segment as shown, and a reciprocable spring pressed push button I46. A strip of spring metal I48 is attached to the upper end of the push button I46 and contacts the ratchet wheel I44. The push button I46 extends into the path of travel of the pin'l I8, and at every charge stroke of the motor the pin II8 strikes the push button I46 causing it to move upwardly against the compression of its spring, and causing the member I48 to move the ratchet wheel I44 one notch in a clockwise direction.

10 The actuator switch 50 is rotatably secured to the bracket I 42 by means of a pivot pin I50. Protruding from therearward side of the pivot pin I50 is a finger I52 which contacts the ratchet wheel I 44 and which is urged rotatably in a clockwise direction by spring I54 coiled about the pivot pin I50, one end of spring 54 engaging the rear bracket, the other end of which contacts the finger I52. However, the switch 50 is held in a substantially horizontal position by the contact of the finger I52 with the ratchet wheel I44. The

purpose of the ratchet wheel I44 and the push button I is to cut out the charging unit 20 from the hydraulic system when a predetermined number of charging operations have been made. As has been explained before, an excessive number of charging operations generally indicates that a gun has expended its ammunition or is in some way defective. It is therefore best to out such a gun out from the hydraulic system so as not to reduce the hydraulic pressure excessively or unnecessarily.

The operation of the mechanical charge counter just described is as follows. At every charging stroke the ratchet wheel I44 will be rotated one notch by the spring metal strip I48 attached to the push button I40 whenever it is contacted by the pin I I8. After a given number of movements, the ratchet wheel I44 will be rotated so that the relieved portion or segment is adjacent the finger I52, which, through the pressure of spring I54 causes the end switch unit to rotate in a clockwise direction to the position shown in Figure 4. When in this position the switch 50 remains continuously in a closed position. This closed position is maintained by the torsional effect of spring I 54 in rotating the switch 50 clockwise against the cylinder I00. Rotation of switch 50 against cylinder I00 actuates the operator 5I which closes the circuit. As has been described previously when the switch 50 remains in closed position a ground is made for the relay 40 thereby energizing it and keeping the switch 44 open to prevent the flow of fluid from the fluid pressure system through the valve 32 and-the selector valves 80.

To return the gun to normal operation, the ratchet wheel I44 is manually rotated to its starting position, causing switch 50 to once more assume an operative position as shown in Figure 3.

The switch 52 is also shown in Figure 3 and is operated by a switch operator 53, similar to the operator 5I for switch 50. This operator is contacted by the breech pin I04 whenever the breech is closed on the firing chamber.

Another part of the invention relates to brackets I08 and I50 for holding the charging unit to the guns. As shown in Figure 5, which is a section through the rear bracket IIO, the bracket is of a type which may be opened to remove the charging cylinder I00 from the gun 22. A semi-circular locking member I56 is pivoted to the bracket H0 at I58. A clamp member I60 is hinged to the bracket II!) at .I62 and acts through a screw I04 to clampthe locking member I50 around the fitting I30 of the charging cylinder I00. When it is desired to dismount the charging cylinder I00 the screw E46 is loosened, the clamp swung downwardly and the locking member swung upwardly. In this waythe charging cylinder I50 may be re moved from the gun and the gunremoved without disconnecting the hydraulic circuit. This type of bracket is desirable for removing a gun from its emplacement for repairs, cleaning or replacement, which operations may be performed without disconnecting any hydraulic circuits.

The operation of the system shown in Figure 1 is as follows. The pump 26- is operated byany suitable source of power, and pumps hydraulic fluid from reservoir 24 to accumulator 28. Solenoid valves 32 are now ready to direct hydraulic fluid to conduits 34 when operated by the'electrioal circuit. Conduits 34 direct the fluid from valve 3?. to the charging motors 29 to charge'guns 22.

The electrical system may be conveniently divided into first and second circuits, and afiring circuit. The first circuit comprises a, battery 38, switch 42, openable connection 44, counter-unit or current impulse responsive means 46-45, and electrically operated valve 32. The second circuit comprises the source or battery 38, switch 42, time-delay relay 40, normally open switch 56, switch 52, which is normally closed when the breech bolt is in its forward position of the gun, and normally closed means 54. The firing circuit comprises the battery 38, switch 42, trigger switch 69, relay 54, cut out member 45, and firing motor 62.

The operation of the electrical circuit will now be described with relation to one gun 22, as the operation is identical for the other gun. Ignition switch 42 is first closed, passing current to slow release relay 40 which is normally connected through manual switch 48, which is normally closed, and through switch 52, which is normally closed by the breech bolt when the breech of the gun 22 is closed and from there through. switch 54 which is normally closed when the gun is not firing and is there grounded. Grounding this circuit energizes the relay 49, which acts through bell crank '5 to open switch 44, thus cutting off current to solenoid valve 32. When it is desired to fire the gun, safety switch 58 is first closed, and then trigger switch 88 is closed. The firing motor 62 is operated by the current from switch 60 and the gun begins to fire. At the same time relay 64 is energized, which breaks the ground of relay. 40 at switch 54.

When the ground of relay 4! is broken at switch 54, there is a tendency for the relay 40 to release the bell crank 56, closing switch 44. However, relay 4D is a slow release relay having a release period greater than the interval between shots of the gun to which the charging mechanism is affixed. Since the same switch operation that breaks the ground of relay 4! at switch 54 also energizes the firing motor 62, the gun 22 will fire at the same time switch 54 is broken, and the breech bolt reciprocates, alternately closing and opening switch 50. relay 4%, energizing. relay 40 so that it will continue to maintain switch 44 in an open position.

If the gun jams during a firing period actuator switch 50 remains continuously open becauselthe breech bolt will not reciprocate, and the relay 40.

becomes deenergized at the end of its time period causing switch 44 to close. Solenoid valve- 32 then opens, passing fluid to the fluid motor 20 which charges the gun by retractingthe breech bolt of the gun, ejecting the dud shell and inserting a fresh ones When the breech bolt reaches its most retracted position it acts on operator 5i. to close switch 5%, thereby grounding relay 4% and breaking the connection to solenoid valve 32. If the. trigger system is still inv afiring. condition the gun will oncemore fire uponthebre'echbolt closing and contacting the. cartridgechamber.

If the firing control is cut oil during the charging stroke it is desirable to continue the charging operation so that a fresh cartridge willbe inthe Closing switch 50 grounds firing chamber for the next firing period and this operation is as follows. Upon cessation of firing, relay 64- is deenergized and switch 54 is thereby closed. Relay 49 is not-grounded, however, as the first movement in the charging cycle forces the breech bolt backwardly opening switch 52. Because switch 52 is open the ground of relay is broken during the charging cycle until the breech bolt reaches the end of its reciprocatory move ment, at which time relay 40 is grounded through switch 50, and valve 32 is thereby closed. The charging operation inserts fresh shell in the firing chamber and the gun is once-more ready for firing when the trigger is actuated.

Often when a period of fire is over it isdesirable to reload the machine gun 22 by inserting a fresh belt of ammunition into the mechanism of the gun. The old belt is removed from the gun and a new belt inserted into the gun. The charging operations necessary to place a cartridge of the new belt intothe gun can be performed by the charging system. The armorer pulls on rin 18, opening switch 52, breaking the connection to ground for relay 40. If ring '58 is pulled to keep switch 52 open for a period longer than the time interval of relay 4i), the deenergization of relay 40 will release bell crank 56: closing switch 44, which actuates valve 32, charging the system. This first charging stroke ejects the live shell in the firing chamber. The first link in a new belt is then inserted in the feedway of gun 22, and ring 18 is again pulled, allowing the gun pawl to engage the first live round. Following these operations, one morecharging cycle must be performed before the gun will fire. This charge is usually performed by the gunner, just prior to combat by manually opening switch 48. This charging sequence is followed to provide an added safety feature inasmuch as the gun cannot be fired until this final charge is made.

The electrical charge counter cuts out a gun which requires an excessive number of charges, as such a gun is probably defective, and the operation is as follows. At every charge, solenoid 16 is energized, pulling on ratchet arm- 12 which in turn rotates conductor-member 66 about its pivot 68. The current meantime flows from brushes") through the conductor to operate valve 32. After a predetermined number of charges have been made, the ratchet will have rotated conductor member out of contact with one of the brushes. In this position of member 66, current can no longer pass to valve 32, and thereafter when gun 22 jams it will not be-charged, but will remain in a jammed condition.

As has been explained before when the charge counter 46 cuts out a misfiring gun the firing motor cut-out 45 likewisecuts out the firing motor 62 of the samegun.

In firing agun it sometimes happens-that-a.

part. will becomestuck or injured so-that a gun will continue to fire regardless. of trigger actuation. Such a gun is known as a runaway gun.

Our invention provides means to control such guns to keepthem from becoming injured by long continued fire. This means is the manually op eratedswitch 48 illustrated as near relay'40. By manually opening switch. 48 the ground connections of. relay Mlare all disconnected and-switch 44 doses passing current to solenoid valve 3?.

Often asin'glecharge is enough to restore a runaway gun to.nor.'- maloperation, but where'this is not sufficient the:

causing it to charge the gun 22.

breech bolt of the guncan be heldin a retracted position by keeping switch 48 open'until the gun.

13 is cooled. to a point where further runaway firing will not injure it. The switch 48 is shown adjacent to the gun, but by using longer. conductors it may be placed near the other manually operated switches 42, 58 and '50.

The operation of the selector valve system shown inFigure 2 is as follows. Ignition switch 42 is first closed passing current to slow release relay 49 which is grounded through switch 59, which is normally closed by the bolt of gun 22 and from there through switch 54, which is closed when the gun is not firing. Grounding this current energizes .the relay 40, which acts through a bell crank 86 to open switch 44 and switch 88, thus cutting 01? current to master valve 32 and selector valve 80. When it is desired to fire the gun, safety switch 58 is first closed, and then trigger switch 60 is closed. The firing motor 62 is operated by current from switch 60 and the gun begins to fire. At the same time relay 64 is energized, breaking the ground of relay 49 at switch 54.

When the ground of relay 4 is broken at switch 54, there is a tendency for relay 40 to release the bell crank 86, close switches 44 and 88. Relay 40 is, however, a slow release relay of any suitable time period greater than the period of automatic fire of the gun 22. Due to this characteristic, relay 40 will hold the bell crank 85 until its time period has elapsed, in the absence of an intervening charging current. Relay as is intermittently grounded, however, through actuator switch 59, and the bell crank 86 is thereby held to keep switches 44 and 88 in an open condition, preventing the operation of master valve 32 and selector valve 80. Actuator switch 50 is intermittently closed by the reciprocating breech bolt of gun 22 striking switch operator 5 I. At every shot of the gun 22, the breech bolt reciprocates and as the time between shots is less than the period of the slow release relay 40, it will be reenergized before its release period has expired.

If one of the guns should jam during a firing period, the relay 40 of the jammed'gun becomes deenergized at the expiration of its release period, and the bell crank 86 moves to close switche 44 and 88. Selector valve 86 now opens, and the movement of its core 84 acts through hell crank 90 to close switch 9|, grounding the current through the solenoid of master valve 32 which then opens to fluid pressure from the accumulator 28. When master valve 32 is operated, high pressure fluid flows into line 82, and through the open selector valve 80 and into the charging motor 20 of the jammed gun, charging that gun by retracting its breech bolt for counter-movement, which action ejects the dud shell and inserts a fresh one. During this charging operation, the selector valve of the other gun remains closed; no fluid can enter its charging mechanism, and the gun continues to fire uninterruptedly. When the breech bolt reaches its most retracted position during the charging stroke, it acts on operator 5| to close the switch 58, thereby grounding relay 40 and breaking the connection to selector valve 80 and master valve 32. The charging mechanism exhausts its charging fluid and the gun is again ready for firing. If the trigger system is still in a firing position, the gun will once more fire upon the breech bolt contacting the cartridge chamber.

Upon cessation of firing, relay 64 is dee ergized; allowing switch 54 to close and establishing a ground for relay 40 through switches 48 and 52. This energizes the relay 451' which acts on bell crank 86 to render master valve 32 and solenoid valve 80 inoperative.

If the firing control is cut ofi during the charging stroke, it is desirable to continue the charging operation so that a fresh cartridge will be in the firing chamber for the next firing period and this operation is as follows. When the charging cycle is started just prior to the cessation of firing, switch 52 is opened, thereby breakingthe ground circuit for relay 48 that is normally established upon cessation of firing. Relay so therefore remains deenergized, and switches 88 and 44 remain closed. When the breech bolt reaches the end of its charging stroke, it causes switch 50 to close thus grounding relay 49, and causing switches 88 and 44 to open, allowing the charging fluid to return to exhaust. By this operation a fresh cartridge is placed in the firing chamber, and the gun is again ready for automatic fire when the trigger is actuated.

The armorers charging operation by pulling on ring 78 is similar to that of Figure l which has already been described. Also the operation for stopping a runaway gun in the system of Figure 2 is similar to that of Figure l, which operation has also been described.

Having described our invention it is not intended to be limited by the specific embodiment herein disclosed. The hydraulic and electrical systems may be changed in many ways and yet fall within our invention. Any fluid could be used in place of a hydraulic fluid in the system disclosed. The devices included in the system may have various different applications and still come within the scope of the invention. Nor is the invention limited in any way other than by the terms of the following claims,

This application is a continuation in part of our copending application Ser. No. 371,742, filed December 26, 1940.

We claim:

l. A gun charging apparatus for use with a gun having a reciprocable breech bolt movable from a normal forward position of the gun to a retracted position thereof and then released for counter movement when charging of the gun is desired, comprising a fluid pressure motor adapted to be mounted on the gun and constructed and arranged to engage the bolt to retract the same, an electrical system including a, source of current and first and second circuits, an electrically operated valve in the first circuit for controlling the flow of fluid to said motor and connected in the first circuit through an openable connection, a time delay relay in the second circuit constructed and arranged to be energized in response to normal reciprocation of the breech bolt to open said openable connection and to be deenergized in response to abnormal reciprocation of the breech boltto permit closing of said openable connection, a switch in the second circuit normally open and constructed and arranged to be closed by the breech bolt when in a retracted position only, to connect the time delay relay in the second circuit to energize said relay, means in the second circuit normally closed to energize the time delay relay at times when the switch is open, a, firing circuit including a firin motor mounted on the gun and a trigger switch interposed between the firing circuit and the source of current, and a relay in the firing circuit constructed and arranged to open said normally closed means when the trigger switch is closed so that energization of the time delay relay must depend upon normal breech bolt reciprocation.

2. A gun charging apparatus for use with a gun having a reciprocable breech bolt movable from 15 a normal forward position of the. n to a retracted. position thereof andv then; released: for countermovement: when chargin of: the gun is desired; comprising a fluid pressure mot'oradap'ted to be mounted. on the. gunand" constructed and arrangedto'engagethe'bclt to retract the same, air-electrical systemlincluding a source of current and first and second circuits, an electrically operated' valve in the first circuitfor. controllin the flow of fluid to said motor and connected in the first circuit through an openable connection, a time delay relay in the second circuit constructed and arranged to be energized in responseto normal reciprocation of the breech bolt to open. said openable' connection and to be deenergi'zed in response to abnormal reciprocation of the breech bolt to permit closing of said openable connection, a switch in the second circuit normally open and constructed and arranged to be closed by the breech bolt when in a retracted position" only, to connect'the time delay relay in the second circuit to energize said relay, means in the second circuit normally closed to energize the'time delay relay at times when the switch is open, amanually operated switch in the secondicircuit normally closed and constructed and arranged'to be opened to deenergize. the time delay relay to manually initiate charging, a firing circuit including a firing'motor mounted on the gun and a trigger switch interposed'between the firing circuit and the source of current, and a relay iii-the firing circuit constructed and arranged toopen said normally closed means when the trigger switch'is closed so that energization of the time delay relay must depend upon normal breech'bolt reciprocation.

3. A' gun charging apparatus for use with a gun having a reciprocable breech bolt' movable from a normal forward position of the gun to a retracted position thereof and then released for countermcvement when charging of the gun is desired, comprisinga fluid pressure motor adaptedto be mounted on the gun and constructed and arranged to engage the bolt to retract the same, an electrical systemincluding a source of current and first and second circuits, an electrically, operatedvalve in the first. circuit for controlling, the flow of fluid to said motor and connected in the first circuit through an openable connection, a timedelay relay in the second circuit constructed and arranged to be energized in response to nor mal reciprocation of the breech bolt to open" said openable connection and to be deenergized in response to abnormal reciprocation. of the breech bolt to permit closin or said-openable connection, a switch in the second circuit normally open and constructed and arranged. to be closed by the breech bolt when in a-retractedposition only, to connectthe time delay relay in-thefsecond circuit to energize said relay, means in the second. circuit 165' normally closed to energize the time delay. relay at times when the switch is open, a switch-in the second circuit constructed and arranged to close when the breech bolt is in its forward position of the gun and to open when the breech bolt is moved toward its retracted position to thereby complete a charging'cycl'e once initiated, a; firing circuit including a, firing motor mounted on the gun and a trigger switch interposed between the lay in the firing circuit constructed and arranged to open said normally closed means and when the' trigger switch is closed so that energization of the time delay relay must depend upon normal breech bolt reciprocation.

s. A gun charging'apparatus for use with a gun having a reciprocable breech bolt movable from a normal forward position of the gun to a retracted position thereof and then released for countermovement when charging of the gun is desired, comprising a fluid pressure motor adapted to be mounted on the gun and constructed and arranged to engage the bolt to retract the same, an electrical system including a source of current and first and second circuits, an electrically operated valve in the first circuit for controlling the flow of fluid to said motor and connected in the first circuit through an openable connection,

a time delay relay in the second circuit constructed and arranged to be energized in response to normal reciprocation of the breech bolt to open said openable connection and to be deenergized in response to abnormal reciprocation of the breech bolt to permit closing of said openable conopen and constructed and arranged to be closed by the breech bolt when in a retracted position only, to connect the time delay relay in the second circuit to energize said relay, means in the second circuit normally closed to energize the time delay relay at times when the switch is open, a firing circuit including a firing motor mounted on the gun and a trigger switch interposed between the firing circuit and the source of cur- GEORGE VJ. PONTIUS, III. ARTHUR P. W'ILSON,

firingcircuit and the source of current, and a re' nection, a switch in the second circuit normally =rent, means in the first circuit responsive to impulses of current to the electrically operated valve,- 

